Soldering system of soldering a dip component on a circuit board

ABSTRACT

A soldering system includes a track, a laying device, a boiler, a shelter, a transmission roller, a position sensor, a thermal radiation heating device, and a driving device. At least one hole is formed on the shelter, and a shape and a dimension of at least one hole on the shelter corresponds to a shape and a dimension of a DIP component. The transmission roller rotates the shelter according to a transmission speed of the track. The position sensor detects a position of a circuit board relative to the boiler. The thermal radiation heating device heats an area on a second surface of the circuit board different from a first surface adjacent to the DIP component through the at least one hole on the shelter continuously, so as to increase a temperature of the second surface when the first surface of the circuit board is passing through the boiler.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of application Ser. No. 13/323,837 filedon Dec. 13, 2011, and the entire contents of which are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a soldering system of soldering a DIPcomponent on a circuit board, and more particularly, to a solderingsystem capable of increasing temperature of the circuit board by thermalradiation for soldering the DIP component on the circuit board.

2. Description of the Prior Art

There are two common types of print circuit board assembly (PCBA)process, surface mount technology (SMT) and direct insertion process(DIP). The conventional direct insertion process includes piercing a DIPcomponent through a circuit board, laying fluxer on the circuit board,preheating the circuit board, and flowing molten tin between the DIPcomponent and the circuit board by a boiler. Furthermore, the circuitboard is preheated by a preheater before the circuit board enters intothe boiler. The preheater can be an infrared preheater or a convectionpreheater. The preheater is for increasing temperature of the circuitboard, and then the track conveys the circuit board to the boiler.Generally, a surface of the circuit board facing the boiler is asoldering surface, and the other surface of the circuit board oppositeto the soldering surface is a heat-dissipating surface. When the moltentin from the boiler flows between the DIP component and the circuitboard through the soldering surface of the circuit board, heat from thecircuit board is dissipated through the dissipating surface excessively.The molten tin cannot flow deeply into a gap between the DIP componentand the circuit board due to large temperature difference between twosurfaces of the circuit board, so that soldering efficiency of themolten tin inside the circuit board and soldering quality of theconventional direct insertion process are decreased. Thus, design of asystem capable of keeping uniform temperature between the two surfacesof the circuit board is an important issue in the PCBA process.

SUMMARY OF THE INVENTION

The present invention provides a soldering system capable of increasingtemperature of the circuit board by thermal radiation for soldering theDIP component on the circuit board for solving above drawbacks.

According to the disclosure, a soldering system for direct insertionprocess includes a track, a laying device, a boiler, a shelter, atransmission roller, a position sensor, a thermal radiation heatingdevice, and a driving device. The track is for transmitting a circuitboard. At least one DIP component pierces through the circuit board. Thelaying device is disposed on a first section of the track for layingfluxer on the circuit board. The boiler is disposed on a second sectionof the track for providing molten tin to flow between the DIP componentand the circuit board through a first surface of the circuit board whenthe first surface of the circuit board is passing through the boiler. Atleast one hole is formed on the shelter, and a shape and a dimension ofthe at least one hole on the shelter corresponds to a shape and adimension of the DIP component. The transmission roller is disposed on aside of the shelter for rotating the shelter according to a transmissionspeed of the track. The position sensor is disposed on a side of thetrack for detecting a position of the circuit board relative to theboiler. The thermal radiation heating device is disposed on the secondsection of the track and opposite to the boiler. The shelter is disposedbetween the thermal radiation heating device and the circuit board. Thethermal radiation heating device is for heating an area on a secondsurface of the circuit board different from the first surface adjacentto the DIP component through the at least one hole on the sheltercontinuously, so as to increase a temperature of the second surface whenthe first surface of the circuit board is passing through the boiler andthe molten tin from the boiler is flowing between the DIP component andthe circuit board through the first surface of the circuit board, tomake the temperature of the second surface of the circuit board besubstantially equal to a temperature of the first surface of the circuitboard so that the molten tin from the boiler goes deeply into a gapbetween the DIP component and the circuit board before the molten tin issolidified. The driving device is electrically connected to the positionsensor for driving the transmission roller to rotate the shelter and formoving the shelter and the thermal radiation heating device relative tothe circuit board according to a detecting result of the positionsensor. A rotary speed of the shelter corresponds to a conveying speedof the circuit board conveyed by the track so that the at least one holeon the shelter continuously aims at the area on the second surfacedifferent from the first surface of the circuit board adjacent to theDIP component.

According to the disclosure, the soldering system further includes apreheater disposed between the first section and the second section ofthe track for preheating the circuit board before the circuit boardpasses through the boiler.

According to the disclosure, the preheater is a convection preheater.

According to the disclosure, heating temperature of the circuit board bythe preheater is smaller than heating temperature of the circuit boardby the thermal radiation heating device.

According to the disclosure, the soldering system further includes acleaner disposed on the second section of the track for exhausting smokegenerated from the boiler.

The soldering system of the present invention utilizes the thermalradiation heating device to accurately heat the area on the circuitboard around the DIP component through the holes on the shelter when themolten tin from the boiler flows between the circuit board and the DIPcomponent, and utilizes the position sensor and the driving device tomove the thermal radiation heating device and the shelter relative tothe circuit board, so that the thermal radiation heating device cancontinuously heat the soldering area on the circuit board for increasingthe soldering efficiency of the soldering system of the presentinvention.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a soldering system for DIP process according toan embodiment of the present invention.

FIG. 2 is a sectional view of a DIP component piercing through a circuitboard according to the embodiment of the present invention.

FIG. 3 is an assembly diagram of a thermal radiation heating device anda shelter according to the embodiment of the present invention.

FIG. 4 is a schematic view of the thermal radiation heating deviceaccording to the embodiment of the present invention.

FIG. 5 is a flow chart of a method for the DIP process according to theembodiment of the present invention.

DETAILED DESCRIPTION

Please refer to FIG. 1. FIG. 1 is a diagram of a soldering system 10 forDIP process according to an embodiment of the present invention. Thesoldering system 10 is for soldering a DIP component 12 on a circuitboard 14. The soldering system 10 includes a track 16, a laying device18, a preheater 20, a boiler 22 and a thermal radiation heating device24. Please refer to FIG. 2. FIG. 2 is a sectional view of the DIPcomponent 12 piercing through the circuit board 14 according to theembodiment of the present invention. The track 16 can be a conveyorbelt, which is inclined relative to a horizontal plane about 5-7degrees, for conveying the circuit board 14 to the boiler 22. At leastone DIP component 12 pierces through the circuit board 14 beforestarting the DIP process. The laying device 18 is disposed on a firstsection S1 of the track 16 for laying fluxer on the circuit board 14when the circuit board 14 wherethrough the DIP component 12 pierces isconveyed to the first section 51 by the track 16, so as to solder theDIP component 12 on the circuit board 14 easily. Then, the circuit board14 passes through the preheater 20 for increasing temperature of thecircuit board 14, so as to enhance soldering efficiency of the DIPprocess. The preheater 20 can be a convection preheater or an infraredpreheater.

Boiler 22 of the soldering system 10 is disposed on a second section S2of the track 16 different from the first section 51. The circuit board14 is conveyed to the second section S2 by the track 16 after thecircuit board 14 is preheated, and then a first surface 141 of thecircuit board 14 passes through the boiler 22. The boiler 22 providesmolten tin to flow between the DIP component 12 and the circuit board 14through the first surface 141 of the circuit board 14. The thermalradiation heating device 24 is disposed on the second section S2 of thetrack 16 and opposite to the boiler 22 for heating a second surface 143of the circuit board 14 different from the first surface 141 when thecircuit board 14 is located at the second section S2 of the track 16, soas to increase temperature of the second surface 143 for increasing thesolder efficiency of the molten tin inside the circuit board 14 in theDIP process. The preheater 20 is disposed between the first section 51and the second section S2 of the track 16 for preheating the circuitboard 14. Upper limit of preheating temperature of the preheater 20 isaround 120° C. The thermal radiation heating device 24 heats an area onthe circuit board 14 adjacent to the DIP component 12, and upper limitof heating temperature of the thermal radiation heating device 24 isaround 268° C. Preheating temperature of the preheater 20 issubstantially smaller than heating temperature of the thermal radiationheating device 24.

The soldering system 10 can further includes a cleaner 26 disposed onthe second section S2 of the track 16 for exhausting smoke generatedfrom the boiler 22. The soldering system 10 can further includes ashelter 28 disposed between the thermal radiation heating device 24 andthe circuit board 14. At least one hole 281 can be formed on the shelter28. A shape and a dimension of the hole 281 on the shelter 28 cancorrespond to a shape and a dimension of the DIP component 12. Forexample, as a top of the DIP component 12 has a circular form, the hole281 can conform to the annular form and the diameter of the annular hole281 can be slightly greater than the diameter of the top of the DIPcomponent 12, so that the DIP component 12 can be covered by the shelter28 without being heated by the thermal radiation heating device 24. Thethermal radiation heating device 24 heats non-heatproof components ornon-plastic parts of the DIP component 12 (such as metal pins of the DIPcomponent 12) on the circuit board 14, which means the thermal radiationheating device 24 heats heatproof parts of the DIP component 12 (such asmetal pins) or areas on the circuit board abound the DIP component 12(such as a circular area around the DIP component 12 in FIG. 1). Thesoldering system 10 can further includes a transmission roller 29disposed on a side of the shelter 28 for rotating the shelter 28according to a conveying speed of the circuit board 14 by the track 16,so as to align the hole 281 on the shelter 28 with the area on thecircuit board 14 around the DIP component 12.

Please refer to FIG. 3 and FIG. 4. FIG. 3 is an assembly diagram of thethermal radiation heating device 24 and the shelter 28 according to theembodiment of the present invention. FIG. 4 is a schematic view of thethermal radiation heating device 24 according to the embodiment of thepresent invention. As shown in FIG. 3 and FIG. 4, the hole 281 can becomposed of a plurality of half circular apertures (or a plurality ofhalf square apertures). Shapes of the apertures are not limited to theabove-mentioned embodiment, and it depends on actual demand. The shelter28 can be directly disposed on an outer side of the thermal radiationheating device 24. The thermal radiation heating device 24 can be aninfrared heat source for heating through the hole 281 on the shelter 28.The soldering system 10 can further include a position sensor 30disposed on a side of the track 16 for detecting a position of thecircuit board 14 relative to the boiler 22. The soldering system 10 canfurther include a driving device 32 electrically connected to theposition sensor 30 for moving the shelter 28 and the thermal radiationheating device 24 relative to the circuit board 14 according to adetecting result of the position sensor 30 when the circuit board 14 isconveyed to the second section S2 of the track 16 and is sensed by theposition sensor 30. Thus, the thermal radiation heating device 24 canheat the area on the second surface 143 of the circuit board 14 aroundthe DIP component 12 through the hole 281 on the shelter 28.

Please refer to FIG. 5. FIG. 5 is a flow chart of a method for the DIPprocess according to the embodiment of the present invention. The methodincludes following steps:

Step 100: Pierce the DIP component 12 through the circuit board 12.

Step 102: The track 16 conveys the circuit board 14 to the first section51 for laying the fluxer on the circuit board 14.

Step 104: Preheat the circuit board 14 by the preheater 20 when thecircuit board 14 moves away from the first section 51.

Step 106: Actuate the cleaner 26 before the circuit board 14 moves intothe second section S2.

Step 108: The circuit board 14 moves into the second section S2 so thatthe first surface 141 of the circuit board 14 passes through the boiler22.

Step 110: The position sensor 30 detects the position of the circuitboard 14 relative to the boiler 22 when the circuit board 14 moves intothe second section S2.

Step 112: The driving device 32 drives the shelter 28 and the thermalradiation heating device 24 to move relative to the circuit board 14according to the detecting result of the position sensor 30 so that thethermal radiation heating device 24 heats the area on the circuit board14 around the DIP component 12 through the hole 281 on the shelter 28.

Step 114: The molten tin from the boiler 22 flows between the DIPcomponent 12 and the circuit board 14 through the first surface 141 ofthe circuit board 14.

Detailed introduction is described as follows. The DIP component 12 canpierce through the circuit board 14 manually or by an automaticmechanism. The track 16 conveys the circuit board 14 to the firstsection S1, so as to lay the fluxer on the circuit board 14 by thelaying device 18. Before the circuit board 14 enters the boiler 22,which means the circuit board 14 moves away from the first section S1 ofthe track 16 and does not enter the second section S2 yet, the circuitboard 14 is preheated by the preheater 20 for increasing the solderingefficiency of the DIP process. Generally, the preheater 20 can be aninfrared preheater or a thermal convection preheater. The upper limit ofheating temperature of the DIP component is around 150° C. When thecircuit board 14 is preheated more than 120° C., temperature of the DIPcomponent 12 may be greater than its upper limit (150° C.). Hence, thepreheating temperature of the circuit board 14 by the preheater 20 isnormally smaller than 120° C.

Then, the cleaner 26 is actuated for exhausting the smoke generated fromthe boiler 22 when the circuit board 14 enters the second section S2.After the track 16 conveys the circuit board 14 to the second sectionS2, the first surface 141 of the circuit board 14 passes through theboiler 22. Meanwhile, the molten tin from the boiler 22 flows betweenthe DIP component 12 and the circuit board 14 through the first surface141 of the circuit board 14. For increasing the soldering efficiency ofthe molten tin inside the circuit board 14, the soldering system 10 ofthe present invention utilizes the thermal radiation heating device 24to heat the second surface 143 of the circuit board 14, so as toincrease the temperature of the second surface 143 for preventing thetemperature of the second surface 143 from being much smaller than thetemperature of the first surface 141.

When the molten tin flows between the DIP component 12 and the circuitboard 14 through the first surface 141 of the circuit board 14, themolten tin solidifies rapidly and does not flow deeply into a gapbetween the DIP component 12 and the circuit board 14 as the temperatureof the first surface 141 is much greater than the temperature of thesecond surface 143 of the circuit board 14. On the other hand, as thetemperature of the first surface 141 of the circuit board 14 issubstantially equal to the temperature of the second surface 143, themolten fin from the boiler 22 can effectively go deeply into the gapbetween the DIP component 12 and the circuit board 14 before the moltenfin is solidified, so that the soldering efficiency of the solderingsystem 10 of the present invention can be increased, such as beinggreater than about 150 percents of an efficiency of the conventionalsoldering system without the thermal radiation heating device, andsoldering quality of the present invention can be enhancedcorrespondingly. Thus, the thermal radiation heating device 24 of thepresent invention can heat the other side of the circuit board 14opposite to the boiler 22 (which means the second surface 143) when thecircuit board 14 enters the second section S2 and the molten tin fromthe boiler 22 flows between the DIP component 12 and the circuit board14, so as to keep the temperature of the second surface 143 close to thetemperature of the first surface 141.

It should be mentioned that temperature of the molten tin from theboiler 22 is around 268° C., so that the thermal radiation heatingdevice 24 heats the second surface 143 of the circuit board 14 to 268°C., so as to ensure the temperature of the second surface 143 is closeto the temperature of the first surface 141. However, the upper limit ofheating temperature of the DIP component 12 is 150° C. Accordingly, theshelter 28, the transmission roller 29, the position sensor 30 and thedriving device 32 of the soldering system 10 are for heating the area onthe second surface 143 of the circuit board 14 around the DIP component12 with the thermal radiation heating device 24. Amounts, shapes anddimensions of the holes 281 on the shelter 28 correspond to amounts,shapes and dimensions of the DIP component 12 piercing through thecircuit board 14. The shelter 28 is disposed between the thermalradiation heating device 24 and the circuit board 14, so that heatradiation generated by the thermal radiation heating device 24 can heatthe predetermined area (which means the area on the second surface 143of the circuit board 14 adjacent to the DIP component 12) on the circuitboard 14 through the holes 281, and does not heat areas on the secondsurface 143 of the circuit board 14 where the DIP component is notlocated.

In addition, the circuit board 14 is conveyed by the track 16, and theposition sensor 30 can detect the position of the circuit board 14relative to the boiler 22 on the track 16. Then, the driving device 32can drive the transmission roller 29 to move the shelter 28 and thethermal radiation heating device 24 relative to the circuit board 14according to the detecting result of the position sensor 30. Rotaryspeed of the shelter 28 corresponds to conveying speed of the circuitboard 14 conveyed by the track 16, so that the thermal radiation heatingdevice 24 can continuously heat the predetermined area on the circuitboard 14 (the area adjacent to the DIP component 12 as shown in FIG. 1)through the hole 281 on the shelter 28. Therefore, the soldering system10 of the present invention can heat the second surface 143 fordecreasing temperature difference between the two surfaces of thecircuit board 14, so as to increase the soldering efficiency of themolten tin inside the circuit board 14.

Comparing to the prior art, the soldering system of the presentinvention utilizes the thermal radiation heating device to heat thedissipating surface (the second surface) of the circuit board when thesoldering surface (the first surface) of the circuit board passesthrough the boiler, so as to decrease the temperature difference of thetwo surfaces of the circuit board for increasing the solderingefficiency. Because the heating temperature of the thermal radiationheating device is greater than the heatproof temperature of the DIPcomponent, the soldering system of the present invention disposes theshelter between the thermal radiation heating device and the circuitboard for protecting the area on the circuit board without soldering.Heat generated by the thermal radiation heating device is transmitted byradiation, so the thermal radiation heating device can heat thesoldering area (the area on the circuit board around the DIP component)through the holes on the shelter accurately, and electronic componentsdisposed on the area without soldering are not heated and destroyed. Inaddition, the position sensor and the driving device of the solderingsystem can move the thermal radiation heating device and the shelterrelative to the circuit board according to the position of the circuitboard relative to the boiler, so that the thermal radiation heatingdevice can continuously heat the soldering area on the circuit boardwhen the circuit board is within the second section of the track, so asto increase the soldering efficiency of the soldering system of thepresent invention.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A soldering system for direct insertion process,comprising: a track for transmitting a circuit board, at least one DIPcomponent piercing through the circuit board; a laying device disposedon a first section of the track for laying fluxer on the circuit board;a boiler disposed on a second section of the track for providing moltentin to flow between the DIP component and the circuit board through afirst surface of the circuit board when the first surface of the circuitboard is passing through the boiler; a shelter, at least one hole beingformed on the shelter, and a shape and a dimension of the at least onehole on the shelter corresponding to a shape and a dimension of the DIPcomponent; a transmission roller disposed on a side of the shelter forrotating the shelter according to a transmission speed of the track; aposition sensor disposed on a side of the track for detecting a positionof the circuit board relative to the boiler; a thermal radiation heatingdevice disposed on the second section of the track and opposite to theboiler, the shelter being disposed between the thermal radiation heatingdevice and the circuit board, the thermal radiation heating device beingfor heating an area on a second surface of the circuit board differentfrom the first surface adjacent to the DIP component through the atleast one hole on the shelter continuously, so as to increase atemperature of the second surface when the first surface of the circuitboard is passing through the boiler and the molten tin from the boileris flowing between the DIP component and the circuit board through thefirst surface of the circuit board, to make the temperature of thesecond surface of the circuit board be substantially equal to atemperature of the first surface of the circuit board so that the moltentin from the boiler goes deeply into a gap between the DIP component andthe circuit board before the molten tin is solidified; and a drivingdevice electrically connected to the position sensor for driving thetransmission roller to rotate the shelter and for moving the shelter andthe thermal radiation heating device relative to the circuit boardaccording to a detecting result of the position sensor, wherein a rotaryspeed of the shelter corresponds to a conveying speed of the circuitboard conveyed by the track so that the at least one hole on the sheltercontinuously aims at the area on the second surface different from thefirst surface of the circuit board adjacent to the DIP component.
 2. Thesoldering system of claim 1, further comprising: a preheater disposedbetween the first section and the second section of the track forpreheating the circuit board before the circuit board passes through theboiler.
 3. The soldering system of claim 2, wherein the preheater is aconvection preheater.
 4. The soldering system of claim 2, whereinheating temperature of the circuit board by the preheater is smallerthan heating temperature of the circuit board by the thermal radiationheating device.
 5. The soldering system of claim 1, further comprising:a cleaner disposed on the second section of the track for exhaustingsmoke generated from the boiler.